“ For the purposes of this regulation a person shall be deemed not to have failed to have done anything required to be done within a limited time if he— (a) did it within such further time as the Board allowed; or (b) had a reasonable excuse for the failure and if that excuse ceased, did it without unreasonable delay after that excuse ceased .”
“ Where an Act authorises or requires any document to be served by post (whether the expression “serve” or the expression “give” or “send” or any other expression is used) then, unless the contrary intention appears, the service is deemed to be effected by properly addressing, pre-paying and posting a letter containing the document and, unless the contrary is proved, to have been effected at the time at which the letter would be delivered in the ordinary course of post .”